Class: Tuile::Component::Layout

Inherits:
Component
  • Object
show all
Defined in:
lib/tuile/component/layout.rb,
lib/tuile/component/layout/box.rb,
lib/tuile/component/layout/absolute.rb,
lib/tuile/component/layout/vertical.rb,
lib/tuile/component/layout/horizontal.rb,
sig/tuile.rbs

Overview

A layout doesn't paint anything by itself: its job is to position child components. Three ways to use one, all top-down (see book ch3):

  • Subclass Layout and compute every child's rectangle yourself in a #relayout override. Total control, and the base for anything unusual:

    class SplitPane < Component::Layout
def initialize
  super
  add(@sidebar = Component::List.new)
  add(@main = Component::Window.new("Main"))
end

protected

def relayout
  left = width * 4 / 10
  @sidebar.rect = Rect.new(0, 0, left, height)
  @main.rect = Rect.new(left, 0, width - left, height)
end
end

    The framework runs it after a resize, an add or remove, and a child's #visible=.

  • Absolute — you give each child a fixed Rect and the layout assigns exactly that.

  • Box / Vertical / Horizontal — you declare each child's extent as a Fixed, Percent or Expand constraint — a Percent optionally bounded with Percent#clamp — and the layout does the arithmetic.

Children that fully tile the layout's rect repaint themselves and cover everything; children that leave gaps (e.g. a form with widgets of varying widths) trigger #repaint's default behavior — the background is cleared and children are re-invalidated so they paint over a clean surface.

Direct Known Subclasses

FormLayout

Defined Under Namespace

Modules: Constraint Classes: Absolute, Box, Clamp, Expand, Fixed, Horizontal, Insets, Percent, Vertical

Instance Method Summary collapse

Instance Method Details

#add(child) ⇒ void

This method returns an undefined value.

Adds a child component to this layout.

@param child

Parameters:



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# File 'lib/tuile/component/layout.rb', line 301

def add(child)
  if child.is_a? Enumerable
    child.each { add(_1) }
  else
    add_child(child)
  end
end

#focusable? ⇒ Boolean

Layouts are focusable containers — like Window and Popup, they don't accept input themselves but they need to participate in the HasContent focus cascade so a Popup wrapping a Layout wrapping a TextField ends up focusing the field rather than parking focus on the popup. Layouts don't paint any visible chrome of their own (the auto-cleared background is just blank space), so this has no mouse-routing consequences — clicks on a gap area land back on the Layout itself and the handle_focus cascade forwards to a tab stop.

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/layout.rb', line 296

def focusable? = true

#handle_focus ⇒ void

This method returns an undefined value.



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# File 'lib/tuile/component/layout.rb', line 320

def handle_focus
  super
  # Forward focus to the first interactive widget in the subtree so the
  # user can start typing / cursoring immediately. Prefer a {#tab_stop?}
  # descendant (TextField, List, Button…) so we skip past intermediate
  # containers like a {Window} or another {Layout}. Fall back to the
  # first focusable direct child for the rare case where the layout has
  # focusable but non-tab-stop children (e.g. an empty {Window}).
  #
  # Both halves skip hidden subtrees — this is the cascade that would
  # otherwise walk straight back into the pane just hidden.
  first_tab_stop = nil
  walk_shown_tree { |c| first_tab_stop ||= c if !c.equal?(self) && c.tab_stop? }
  if first_tab_stop
    screen.focused = first_tab_stop
  else
    first_focusable = @children.find { _1.visible? && _1.focusable? }
    screen.focused = first_focusable unless first_focusable.nil?
  end
end

#remove(child) ⇒ void

This method returns an undefined value.

@param child

Parameters:



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# File 'lib/tuile/component/layout.rb', line 311

def remove(child)
  raise TypeError, "expected Component, got #{child.inspect}" unless child.is_a? Component
  raise ArgumentError, "#{child}'s parent is #{child.parent}, not this layout #{self}" if child.parent != self

  remove_child(child)
  invalidate if @children.empty? # nothing left to paint over the gap
end